The c-type lectin, Mincle, is a macrophage receptor for Candida albicans. (2007-2009)

The yeast Candida albicans is an important opportunistic infection that causes both mucosal and disseminated disease in patients whose innate or adaptive immune responses are impaired Infection and proliferation results in fungal colonisation of the tissues, and a variable degree of tissue damage. The latter is determined both by the virulence properties of the organism and by the genetic makeup of the host. This large, extracellular pathogen is eradicated from the body predominantly by acavenger (phagocytic) cells, which are also important in determining the severity of the associated tissue lesions. A phagocytic cell that is central to both innate and adaptive immune responses is the macrophage, which not only takes up and kills the yeast, but also is capable of of killing and digesting it, and presenting the components to cells of the adaptive immune system. This project is based on the postulate that the outcome and severity of infection is determined, at least in part, by the early functional response of the macrophage to the overall virulence properties of the yeast. The response is initiated by interactions with cell-surface receptors, and this study will show that a novel macrophage receptor, Mincle, is an important part of the innate immune response to fungal infections. We have shown that it is associated with differences in susceptibility to yeast infections in inbred mouse strains; it can discriminate between different isolates of the yeast; and it initiates the inflammatory signalling cascade. Our project will define the specific role of this receptor in fungal infection. The results will be important in understanding the basic biology of host resistance, and will offer new opportunities for therapeutic intervention by selectively blocking or modifying different activation pathways.